Matthieu BRAVIN

39 year-old, married, 2 children

Researcher, CIRAD

Research group: Recycling and risk



CIRAD, Station de la Bretagne

40 chemin Grand Canal, CS 12014

97743 Saint-Denis cedex 9

La Réunion, France

Ph. : +262 262 52 80 30+262 262 52 80 30

Secr. : Ph. - 80 20 / Fax. - 80 21




Biogeochemistry of Trace Elements

in Agricultural Soils


My Research Issue

Anthropogenic activities can involve a contamination of agricultural soils in trace elements. When accumulating in soils, trace elements can become highly bioavailable to plants (i.e. phytoavailability). This can involve, on one hand, the appearance of phytotoxicity tied up with a lowering of soil fertility and, on another hand, a contamination of the food chain (i.e. phytoaccumulation).

More particularly, spreading of organic wastes (e.g. sewage sludges, cattle manures...), in spite of the agronomic and economic benefits, favours trace elements accumulation in agricultural soils. In parallel, organic waste spreading alters the turnover of soil organic matters, thereby acting as a major driver of trace element phytoavailability in soils.

My research therefore aims at characterising and evaluating trace element phytoavailability and more particularly in the specific context of the agricultural recycling of organic wastes. To reach these objectives, my research focuses on two complementary approaches:

  • A mechanistic approach, dedicated to the understanding of the major biogeochemical drivers of trace element dynamic at the soil-roots interface (i.e. within the rhizosphere),


  • A risk-assessment approach, dedicated to the development of a biological test, the RHIZOtest, for the assessment of trace element phytoavailability in soils.


Educational Background

- 2005-2008: Ph.D, Join Research Unit Biogeochemistry of soil and rhizosphere (INRA-SupAgro, Montpellier, France), supervisor: Philippe Hinsinger

  • Title : Rhizosphere processes determining copper bioavailability to durum wheat cropped in former vineyard soils


- 2004-2005: Master degree in Soil Science (SupAgro, Montpellier, France)


- 2001-2004: Master degree in Agronomy, Engineering college of Agriculture (ENITA, Clermont-Ferrand, France)


Scientific and Technical Skills


  • Plant growth in hydroponics or with soils in growing chamber
  • Field (soil adhering to roots) and laboratory (root-mat technique) sampling of rhizosphere
  • Soil solution sampling using micro-succion cups (Rhizon) and centrifugation
  • Assessment of trace element phytoavailability using the RHIZOtest technique



  • Trace metal (Cu) speciation with ionic-selective electrode
  • Selective and sequential chemical extraction of trace elements in soil
  • Extraction des éléments traces du sol par échantillonneur passif (DGT)
  • Chemical extraction of trace metals from root apoplasm
  • Digestion of plant material using micro-wave  oven
  • Total trace elements in solution (digests, soil solution, soil extracts...) using F-AAS, GF-AAS and ICP-AES
  • Dissolved organic carbon in soil solution using TOC-meter



  • Geochemistry & speciation: GEOCHEM, PHREEQC et WHAM VI
  • Reactive transports: DIFS-1D/2D, PHREEQC


Research Projects

On going

9. RHIZOlab: RHIZOtest validation through an international ring-test in the scope of ISO standardisation; 2012, ADEME, 80 k€, coordinator.


8. PILMO: Organic waste management and environmental impacts; 2011-2013, CIRAD-La Réunion region-French government.

  • Coordinator of the sub-section PILMO-6 : Impact of organic waste recycling on contaminant dynamic and phytoavailability in agricultural soils; 30 k€/an


7. Towards a generic model (Biotic Ligand Model) to asses trace metal (Cu and Zn) phytoavailability; 2011, INSU (EC2CO-CYTRIX), 25 k€, co-coordinator.


6. Réseau PRO : Setting-up of a field-trial network and database for studying agronomic benefits and environemental and sanitary issues of organic wastes recycled in agriculture; 2011-2013, MAAP, 925 k€, coord. : ACTA.

  • Responsible for the critical review on trace element phytoavailability


5. ISO standard project: ISO/CD 16198 Soil quality – Plant-based test for assessing the environmental bioavailability of trace elements to plants; 2009-2012, ISO-AFNOR, coordinator.


4. NormaRHIZO: Towards the standardisation of the RHIZOtest to assess trace elements phytoavailability in contaminated soils; 2010-2012, ANR (Prog. : Contaminants Ecosystèmes Santé), 500 k€, co-coordinator.


3. ISARD : Ecological intensification of agricultural production systems through organic wastes recycling; 2009-2012, ANR (Prog. : Systerra), 960 k€, coord. : CIRAD.

  • Involved in the task dedicated to the study of trace element dynamic in the soil-plant system amended with organic wastes



2. Copper bioavailability to crops in former vineyard soils – Assessment-tool and biological and biogeochemical drivers; 2005-2006, MEEDDAT (Prog. : PNETOX), 40 k€, coord. : INRA.

  • Basement of my Ph.D


1. Transfer and transformation of arsenic speciation in rice rhizosphere in irrigated paddy fields of Bangladesh; 2004-2005, INSU (Prog. : ECCO-ECODYN), 100 k€, coord. : CNRS.

  • Basement of my master degree in Soil Science: Arsenic bioavailability in reduced soil – effect of phosphate addition and redox conditions in rice rhizosphere




- Join Research Unit CEREGE, team SE3D, Aix-en-Provence, from 2005; J.-M. Garnier, A. Masion, J. Rose (CNRS).

  • Hosted in the team SE3D in 2009-2010
  • Arsenic biogeochemistry  in the rhizosphere
  • Localisation and speciation of trace elements at molecular scale (µXRF, XAS)
  • Characterisation of functional groups responsible for trace metal binding in root apoplasm (FTIR, RMN)


- Join Research Unit Eco&Sols, Montpellier, from 2010; P. Hinsinger (INRA).

  • RHIZOtest development


- French organisation for standardisation (AFNOR), committee T 95 E "Ecotoxicology", from 2009; A. Bispo (ADEME), P. Pandard (INERIS).

  • RHIZOtest standardisation


- IPGP, team Water Geochemistry, Paris, from 2008; M. Benedetti (Université Paris Diderot).

  • Analytical determination of trace metal speciation in soil solution using DMT


- Unit PROTEE, team CAPTE, Toulon, from 2008; C. Garnier, V. Lenoble (University of the South Toulon-Var).

  • Lability of trace metal organic complexes in soil and rhizosphere solutions using voltammetric techniques (DPASV, pseudopolarography)
  • Reactivity of root apoplasm towards trace elements (titration)


- Join Research Unit BPMP, team Plant adaptation to metals, Montpellier, from 2011; P. Berthomieu, J.-C. Davidian (Montpellier SupAgro).

  • Recovering of root apoplasm
  • Selection of contrasted plant genotypes


- Join Research Unit TCEM, Bordeaux, 2005-2010; L. Denaix, C. Nguyen, A. Schneider (INRA).

  • Lability of trace elements in soils using DGT
  • Modelling of trace element phytoavailability according to the Barber-Cushman formalism



- ISO, from 2009; J. Harmsen (Alterra, University of Wageningen, the Netherlands).

  • RHIZOtest standardisation


- Wageningen University and Research Centre, the Netherlands, from 2009; R. Comans.

  • Fractionation of dissolved organic matters in soil solution


- University of life sciences, Norway, 2007; M. Chaudhary.

  • Mitigation of deficiencies in minor nutrients (Cu and Zn) in organic farming with mineral and organic amendments



Post-Docs and Temporary staff


5. C. Nobile (Post-doctorante) 2020-2021 Phosphate fertilisation of sugarcane systems in Réunion. CIR eRcane FertiPC project, 12 months.

4. C. Laurent (Post-doctorante) 2020-2022 Nickel and chromium phytoavailability for marlet-garden and forage crops fertilized with organic amendments in Réunion. Ademe PhytAO-Ni/Cr project, 21 months.

3. N. Oustrière (Engineer) 2013 Prospective assessment of policy constraint and ecotoxicological risk of the long-term accumulation of trace elements in soils amended with orgnaic wastes in Réunion. PILMO project, 12 months.

2. L. Lemal (Engineer) 2011-2012 RHIZOtest optimisation and management of the international ring-test. Projects ANR NormaRHIZO and RHIZOlab (ADEME), 18 months.

1. M. Tella (Post-Doc) 2010-2011 Trace metal dynamic during organic matter mineralisation added to soils, using the DGT technique. Projects ANR ISARD et NormaRHIZO, 18 months.


Ph.D student

6. M. Ramos 2018-... Soil spectral signatures for sugarcane fertiliser recommendations in Réunion. eRcane-Cirad CIFRE scholarship.

5. L. Marastoni 2016-2019 Rhizosphere mechanisms alleviating copper toxicity in vineyard soils. Hosted 4 months, T. Mimmo (superv.), Faculty of Science and Technology of Bolzano, Italy. 

4. C. Laurent 2016-2019 Copper and zinc bioavailability to plants and earthworms : interactionbetween the effets of organic fertilizers on the long-term and soil organisms on the changes in soil physical-chemical properties. Scholarship from Cirad, Conseils Régional et Départemental Réunion (UE Feder) and French ministry of agriculture, food and forest, 190 p..

3. C. Nobile 2017 Phosphorus phytoavailability in agricultural soils of Réunion receiving organic fertilizers on the long-term: Does the application rate the only driver to account for? VEOLIA-CIRAD CIFRE scholarship, 177 p. 

2. T. Djae 2017 Binding capacities of dissolved organic matter toward copper in the soil-plant systems amended with organic wastes products. ADEME-CIRAD scholarship, 177 p. + appendices.

1. S. Guigues 2015 Charactherization of physical-chemical interactions between copper and roots to support the development of a model to assesss trace element phytoavailability. ADEME-CIRAD scholarship, 167 p.


Other students


30. A.-R. Douyère (Master II) 2021 Sugarcane response to phosphorus fertilization in the podelogical context of la Réunion. AgroCampus Ouest, 6 months.

29. V. Matyniak (IUT) 2021  Measurements of pH et copper speciation in the solution of soils receiving an application of organic amendments. IUT Aix Marseille Université, 2 months.

28. C. Honoré (Master II) 2021 Laboratory assessment pf chromium and nickel phytoavailability to market-garden and forage crops in soils fertilized with orgnaic amendments in La Réunion. Master EXCE, Université de Bordeaux, 6 month.

27. I. Aabbar (Master II) 2020  Fate of trace orgnaic contaminants in the soil of a field experiment receiving orgnaic residue application in La Réunion. Université Aix-Marseille Master SET, spécialité MAEVA- GSDP, 6 months.

26. L. Chiarello(Master II) 2018 Impact of the soil-earthworm interaction on the availability and the bioavailability of Cu and Zn in soils receinving organic wastes on the long-term. The University of Montpellier, 6 months.

25. L. Séréni (Master II) 2017-2018 Trace element dynamic in the context of agricultural recycling. Ecole normale supérieure, 6 months.

24. M. Valmier (Master II) 2017 RHIZOtest ability to evidence the efficiency of remediation on soils polluted by trace elements. University of Bordeaux, 5,5 months. 

23. M. Perrot (IUT) 2017 Analytical determination of copper and zinc availability in agricultural soils amended organic wastes on the long-term in Reunion. IUT Robert Schuman, 2.5 months. 

22. C. Grigis (Master II) 2016 Impact of the application of organic and mineral fertilizers on phosphorus availability in agricultural soils of Réunion - Successive incubations of soil under controlled conditions to mimic the long-term effect of application at field-scale. Montpellier SupAgro, 6 months.

21. Q. Devresse (Master II) 2016 Modelling trace element bioavailability and rhizotoxicity to barley (Hordeum vulgare L.) grown in agricultural soils amended with organic wastes. Université de Lorraine, 5.5 months.

20. Q. Chevalier (Master I) 2015 Impacts of organic vs. mineral fertilizers on phosphorus availability in andosols of the island of Reunion. Université de Limoges, 2 months.

19. M. ravelet (Licence) 2015 phosphorus availability in agricultural soils in the island of Reunion. IUT Paul Sabatier, Université Toulouse III, 3.5 months.

18. J. Laude (IUT) 2014 Copper speciation in solution in agricultural soils amended with organic wastes. IUT of Chemistry Orléans, 4 months.

17. A. Edde (Master II) 2014 Contamination in trace elements of agricultural soils amended with organic wastes. ENSAIA Nancy, 6 months.

16. S. Poïny-Toplan (Master II) 2013 Predictive modelling of trace element accumulation in tropical soils of Réunion amended with orgnaic wastes. Universities of Avignon and Réunion, 6 months.

15. C. Pradier (Master I) 2012 Analytical determination and modelling of trace metal speciation in the rhizosphere of three crop species. ENSIP, co-supervision, 3 months.

14. T. Lahbib-Burchard (Master II) 2012 Prediction of mid/long-term accumulation of trace metals in soils following the agricultural recycling of organic wastes and risk-assessment of ecotoxicological issues. ISTOM, 6 months.

13. M. Hutte (Master II) 2012 Availability and phytotoxicity of trace metals following the agricultural recycling of organic wastes in tropical areas: Application to la Réunion Island. ISARA, co-supervision, 6 months.

12. T. Djae (Master II) 2012 Analytical determination and modelling of trace metal speciation in the rhizosphere of three crop species. Master in Chemistry & Material, Specialisation in Environmental analytical chemistry and modelling, co-supervision, 6 months.

11. M. Benedetto (IUT) 2010 Arsenic remobilisation by root activitiesin wheat rhizosphere using sequential extraction. IUT of Chemistry, Marseille, co-supervision, 2 months.

10. V. Bielka (Master I) 2010 Cadmium, copper and nickel speciation in solution in an agricultural soil: impact of organic wastes amendment and root activities in lettuce (Lactuca sativa L.) rhizosphere. Master SET, Aix-en-Provence, 4 months.

9. S. Grimaldi (Master II) 2010 Dynamic of metal remobilisation in saturated soils using the DGT technique. Master Hydrology, Hydrogeology and Soils, Paris, co-supervision, 6 months.

8. M. Hutte (Master II) 2010 Additional investigation on copper speciation in solution in an agricultural soil: impact of organic wastes amendment and root activities in lettuce (Lactuca sativa L.) rhizosphere. co-supervision, 1 month.

7. A. Idrac (Master II) 2010 Temporal dynamic of metal re-supply in soil by coupling DGT measurements and DIFS modelling. Master SET, Aix-en-Provence, co-supervision, 5 months.

6. L. Lemal (Master II) 2010 Selection of standard plant species for the standardisation of the RHIZOtest as a measuring tool of trace element phytoavailability in contaminated soils. Master Environmental Study, Toulouse, co-supervision, 7 months.

5. S. Chataing (Master I) 2009 Characterisation, speciation and bioavailability of trace metals in a broad set of soils and organic wastes. CPE, Lyon, co-supervision, 6 months.

4. A. L. Marti (Master II) 2008 Alkalisation in durum wheat rhizosphere and alteration of copper availability and bioavailability in an acidic, former vineyard soils. Polytechnic University of Valencia, Spain, 5 months.

3. B. Le Merrer (IUT) 2007 Determination of plant copper uptake kinetic parametersfor durum wheat to fill in Barber-Cushman modelling approach. IUT Biology, Brest, 4 months.

2. J.-P. Pegon (Master I) 2007 Optimisation of a biotest to assess copper bioavailability to durum wheat in former vineyard soils. Master BGAE, Montpellier, 3 months.

1. B. Larabi (Master I) 2006 Physical-chemical drivers of copper bioavailability to durum wheat in former vineyard soils – effect of total Cu and  pH of soils. Master in Environmental Engineering, ENSA Rennes, Morocco, 2 months.


Teaching and training


Profesional degree "Agriculture and Sustainable Development in Tropical Island Area", University of Réunion / Agriculture School of Saint Paul

  • Soil contamination by trace elements and agricultural recycling of organic wastes, lecture, 2h X 2
  • Agricultural recycling of organic wastes and environmental risks, Pratical works in the CIRAD experimental station of the Colimaçons, 4h X 2

RHIZOtest european training course, CIRAD Montpellier, coordinator

  • RHIZOtest history, implementation and standardisation, lecture, 1 day
  • Practical works into plant growing facilities, 2 days



Master degree in Environmental analytical chemistry and modelling, University of South Toulon-Var, lectures

  • Bioavailability of soil contaminants: concepts, biogeochemical drivers and risk-assessment tools. 3 h
  • Trace element phytoavailability in soils. 2 h
  • General soil chemistry: composition, properties and reactivity. 3 h



Engineering college of Agronomy, Montpellier SupAgro

  • Copper phytotoxicity. 1 h, lecture
  • How biogeochemical processes drive copper bioavailability to durum wheat – Evidence from the field. 4 h, practical works in the field



Engineering college of Agronomy, Montpellier SupAgro

  • Sampling and analyses of soil. 40 h, field- and laboratory-practical works
  • Introduction to experiments in ecotoxicology. 27 h, practical works in the laboratory

Master degree in behaviour of natural and agricultural ecosystems, Montpellier SupAgro

  • From bibliography to result introduction: Tools to be efficient during your master degree. 3 h, lecture



Master degree in behaviour of natural and agricultural ecosystems, Montpellier SupAgro, Montpellier University

  • Bibliography during the master degree: how to be the most efficient? 3 h, lecture and computer practical works


Reviewing activities


Chemosphere (1)

Ecotox. Environ. Safe  (2)

Environ. Sci. Pollut. Res. (1)

Environ. Sci. Technol. (1)

Environ. Tox. Chem (1)

J. Plant. Physiol (1)

J. Soil. Sed. (1)

Sci. Tot. Environ. (1)



Chemosphere (1)

Environ. Exp. Bot. (1)

Int. J. Environ. Pollut (1)

Pedosphere (1)



Ciência Rural (1)

Ecotox. Environ. Safe  (1)

Environ. Tox. Chem (1)

Geoderma (1)

J. Soil. Sed. (1)

Plant Soil (1)



Archives of Agronomy and Soil Science (1)

Environ. Pollut. (1)

Environ. Sci. Technol. (2)

Planta (1)

Plant Soil (1)



Environ. Pollut. (1)

Environ. Sci. Technol. (1)

J. Soils Sediments (2) 

Plant Soil (3)



Acta Physiol. Plant. (1)

Environ. Sci. Technol. (1)

J. Plant Nutr. Soil Sci. (1)

J. Soil Sci. Plant Nutr. (1)

J. Soils Sediments (1) 

Plant Physiol. (3)

Plant Soil (1)

Plant Soil Environ. (1)



Environ. Chem. (1)

Environ. Sci. Technol. (1)

Int. J. Environ. Anal. Chem. (2)

Plant Soil (1)

Soil Research (1)



Ecotox. Environ. Safe. (1)

Environ. Chem. Lett. (1)

Environ. Pollut. (1)

J. Soils Sediments (1)



Ecotox. Environ. Safe. (1)

J. Agric. Food Chem. (1)

J. Soils Sediments (1)

Plant Soil (3)



Environ. Sci. Technol. (1)


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